Bacterial laccase of Anoxybacillus ayderensis SK3-4 from hot springs showing potential for industrial dye decolorization

Jingjing Wang,Xiaoqing Tang,Wei Li,Qiang Yin,Yang Hu,Yang Yang,Fei Chang

doi:10.1186/s13213-020-01593-6

Abstract

IntroductionLaccases are green biocatalysts that possess attractive for the treatment of resistant environmental pollutants and dye effluents.PurposeTo exploit the laccase of Anoxybacillus ayderensis SK3-4 that possesses dye decolorization ability at room and higher temperature, we characterized the enzyme in considerable detail and investigated its ability to decolorize different dyes.ResultsA bacterial laccase gene designed as LacAn from Anoxybacillus ayderensis SK3-4 of hot springs was cloned and expressed in Escherichia coli. LacAn is a monomeric protein with a molecular weight of 29.8 kDa. The optimum pH and temperature for syringaldazine oxidation were 7.0 and 75 °C, respectively. LacAn was stable at pH values ranging from 6.5 to 8.5 above 65 °C. The enzyme activity was significantly enhanced by Cu2+ and Mg2+ but inhibited by Zn2+ and Fe2+. Furthermore, LacAn showed high decolorization capability toward five dyes (direct blue 6, acid black 1, direct green 6, direct black 19, and acid blue 93) in the absence of redox mediators. It also demonstrated a wide temperature range, and it can retain its high decolorization ability even at high temperatures.ConclusionsThese properties including better enzymatic properties and efficiency to decolorize dyes demonstrate that the bacterial laccase LacAn has potentials for further industrial applications.

Highlights

Laccases are green biocatalysts that possess attractive for the treatment of resistant environmental pollutants and dye effluents.Purpose: To exploit the laccase of Anoxybacillus ayderensis SK3-4 that possesses dye decolorization ability at room and higher temperature, we characterized the enzyme in considerable detail and investigated its ability to decolorize different dyes
Recent studies have discovered that laccases are widespread in bacteria, such as Bacillus tequilensis (Sonica et al, 2014), Caldalkalibacillus thermarum (Sunil et al, 2018), Streptomyces griseorubens (Feng et al, 2015), and Agaricus bisporus (Othman et al, 2018), and their application is common in the industrial field
Bioinformatics analysis has demonstrated the high diversity of laccase or laccase-like enzymes in bacteria (Ausec et al, 2011), but bacterial laccase-like enzymes have yet to be exploited as promising laccase resources

Summary

Results

A bacterial laccase gene designed as LacAn from Anoxybacillus ayderensis SK3-4 of hot springs was cloned and expressed in Escherichia coli. LacAn is a monomeric protein with a molecular weight of 29.8 kDa. The optimum pH and temperature for syringaldazine oxidation were 7.0 and 75 °C, respectively. LacAn was stable at pH values ranging from 6.5 to 8.5 above 65 °C. LacAn showed high decolorization capability toward five dyes (direct blue 6, acid black 1, direct green 6, direct black 19, and acid blue 93) in the absence of redox mediators. It demonstrated a wide temperature range, and it can retain its high decolorization ability even at high temperatures

Conclusions

Introduction

Materials and methods

Results and discussion

Conclusion